WO2009071548A1

WO2009071548A1 - Curable compound comprising silylated polyurethane

Info

Publication number: WO2009071548A1
Application number: PCT/EP2008/066641
Authority: WO
Inventors: Johann Klein; Sara Gonzalez; Lars Zander; Andreas Bolte; Helene Boudet
Original assignee: Henkel Ag & Co. Kgaa
Priority date: 2007-12-03
Filing date: 2008-12-02
Publication date: 2009-06-11
Also published as: DE102007058344A1

Abstract

The present invention relates to a method for producing a silylated polyurethane, comprising: (A) converting (iii) at least one polyol compound A having a molecular weight of 4,000 - 30,000 g/mol and a diisocyanate at a stoichiometric excess of the diisocyanate compound relative to the polyol compound(s) A, followed by adding (iv) one or more polyol compound(s) B having a molecular weight of up to 2,000 g/mol in such an amount that the sum of the polyol compounds A and B are used in stoichiometric excess relative to the diisocyanate compound(s), whereby a hydroxyl-terminated polyurethane prepolymer is formed; and (B) converting the polyurethane prepolymer and one or more isocyanate silane(s) of the formula (I): OCN-R-Si-(R1)m(-OR2)3-m (I), where m is 0, 1 or 2, each R2 is an alkyl radical having 1 to 4 carbon atoms, each R1 is an alkyl radical having 1 to 4 carbon atoms, and R is a difunctional organic group. The invention further relates to compounds comprising the silylated polyurethane that can be so produced, and the use thereof as an adhesive and sealant or coating agent.

Description

"Curable compositions containing silylated polyurethanes"

The present invention relates to silane-crosslinking, curable compositions, their preparation and use in adhesives and sealants and coating compositions.

Polymer systems which have reactive alkoxysilyl groups are known. In the presence of atmospheric moisture, these alkoxysilane-terminated polymers are capable, even at room temperature, of condensing one another with elimination of the alkoxy groups. Depending on the content of alkoxysilyl groups and their structure, mainly long-chain polymers (thermoplastics), relatively wide-meshed three-dimensional networks (elastomers) or highly crosslinked systems (thermosets) are formed.

The polymers typically have an organic backbone bearing alkoxysilyl groups at the ends. The organic skeleton may be, for example, polyurethanes, polyesters, polyethers, etc.

One-component, moisture-curing adhesives and sealants have played a significant role in numerous technical applications for many years. In addition to the polyurethane adhesives and sealants with free isocyanate groups and the traditional silicone adhesives and sealants based on dimethylpolysiloxanes, the so-called modified silane adhesives and sealants have increasingly also been used recently. In the latter group, the major constituent of the polymer backbone is a polyether and the reactive and crosslinkable end groups are alkoxysilyl groups. Compared with the polyurethane adhesives and sealants, the modified silane adhesives and sealants have the advantage of freedom from isocyanate groups, in particular monomeric diisocyanates, furthermore they are distinguished by a broad adhesion spectrum on a large number of substrates without surface pretreatment by primers.

US Pat. No. 4,222,925 A and US Pat. No. 3,979,344 A describe siloxane-terminated organic sealant compositions curable at room temperature based on reaction products of isocyanate-terminated polyurethane prepolymers with 3-aminopropyltrimethoxysilane and 2-aminoethyl-, 3-aminopropylmethoxysilane to isocyanate-free siloxane-terminated prepolymers. However, adhesives and sealants based on these prepolymers have unsatisfactory mechanical properties, in particular with respect to their elongation and tear resistance. For the preparation of silane-terminated prepolymers based on polyethers, the following processes have already been described:

Copolymerization of unsaturated monomers with those having alkoxysilyl groups, e.g. Vinyltrimethoxysilane.

Grafting of unsaturated monomers such as vinyltrimethoxysilane on thermoplastics such as polyethylene.

Hydroxy-functional polyethers are reacted with unsaturated chlorine compounds, e.g.

Allyl chloride, in an ether synthesis in polyether with terminal olefinic

In turn reacted with hydrosilane compounds having hydrolyzable groups, e.g. HSi (OCH) can be converted into silane-terminated polyethers in a hydrosilylation reaction under the catalytic influence of, for example, Group 8 transition metal compounds.

In another method, the polyethers containing olefinically unsaturated groups are reacted with a mercaptosilane, e.g. 3-mercaptopropyltrialkoxysilane reacted. In another method, hydroxyl-containing polyethers are first reacted with di- or polyisocyanates, which in turn are then reacted with amino-functional silanes or mercapto-functional silanes to form silane-terminated prepolymers. Another possibility is the reaction of hydroxy-functional polyethers with isocyanato-functional silanes such as e.g. 3-isocyanatopropyltrimethoxysilane.

These preparation methods and the use of the abovementioned silane-terminated prepolymers in adhesive / sealant applications are mentioned, for example, in the following patents: US Pat. No. 3,971,751, EP-A-70475, DE-A-19849817, US Pat. No. 6,124,387 US Pat. 5990257 US-A-4960844, US-A-3979344, US-A-3632557, DE-A-4029504, EP-A-601021, or EP-A-370464.

EP-A-0931800 describes the preparation of silylated polyurethanes by reacting a polyol component having a terminal unsaturation of less than 0.02 meq / g with a diisocyanate to give a hydroxyl-terminated prepolymer which is then reacted with an isocyanatosilane of the formula OCN-R-Si - (X) _m (-OR ¹ ) _3-m where m is 0.1 or 2 and each R ¹ radical is an alkyl group of 1 to 4 C atoms and R is a difunctional organic group. According to the teaching of this document, such silylated polyurethanes have a superior combination of mechanical properties which cure within reasonable periods of time to a slightly tacky sealant without exhibiting excessive viscosity. WO-A-2003 066701 discloses alkoxysilane and OH-terminated polyurethane prepolymers based on high molecular weight polyurethane prepolymers with reduced functionality for use as binders for low modulus sealants and adhesives. For this purpose, first a polyurethane prepolymer of a diisocyanate having an NCO content of 20 to 60% and a polyol component comprising a polyoxyalkylene having a molecular weight between 3000 and 20,000 as the main component, the reaction at a conversion of 50 to 90% of OH groups should be stopped. This reaction product should then be further reacted with a compound containing alkoxysilane and amino groups. These measures are to obtain prepolymers having a relatively low average molecular weight and low viscosity, which are intended to ensure a high level of properties.

WO-A-2005 042605 discloses moisture-curing alkoxysilane-functional polyetherurethane compositions containing from 20 to 90% by weight of a polyetherurethane A having two or more reactive silane groups and from 10 to 80% by weight of a polyetherurethane B having a reactive silane group. The polyether urethane A is intended to have polyether segments with a number average molecular weight (M _n ) of at least 3000 and an unsaturation of less than 0.04 mequ / g, and the reactive silane groups should be prepared by reacting an isocyanate-reactive group with a compound of the formula OCN-Y- Si (X) _{3 are} inserted. The polyetherurethane B is said to have one or more polyether segments having a number average molecular weight (M _n ) of 1000 to 15000, and the reactive silane groups are to be incorporated by reaction of an isocyanate group with a compound of the formula HN (Ri) -Y-Si (X) ₃ , R ₁ is an alkyl, cycloalkyl or aromatic group having 1 to 12 C atoms, X is an alkoxy group and Y is a linear radical having 2 to 4 C atoms or a branched radical having 5 to 6 C atoms.

In order to reduce the functionality and thus the crosslinking density of moisture-curing alkoxysilane-terminated polyurethanes, WO-A-92/05212 proposes the co-use of monofunctional isocyanates in a mixture with diisocyanates in the synthesis. Monoisocyanates are known to have a very high vapor pressure and are hazardous starting materials because of their toxicity in terms of occupational hygiene.

There remains a need for isocyanate-free compositions for the production of 1K or 2K adhesives and sealants which have an acceptable curing time and, upon curing, a particularly good elasticity and ductility. Furthermore, there is the Desire, for an efficient synthetic route and for compositions which have no residual tackiness.

It is therefore an object of the present invention to provide isocyanate-free crosslinkable compositions which have high elasticity and good extensibility. Furthermore, a user-friendly curing time is desired.

The achievement of the object of the invention can be found in the claims. It consists essentially in the provision of a process for the preparation of a silylated polyurethane, comprising:

(A) React

(i) at least one polyol compound A having a molecular weight of 4,000-30,000 daltons or g / mol with at least one diisocyanate at a stoichiometric excess of the diisocyanate compound (s) or of the diisocyanate (s) relative to the polyol compound ( en) A, followed by the addition

(ii) a polyol mixture containing one or more polyol compound (s) B having a molecular weight of up to 2000 daltons or g / mol in an amount such that the sum of the polyol compounds A and B is in stoichiometric excess over the diisocyanate compound (s) ), thereby forming a polyurethane prepolymer which is hydroxyl-terminated; and

(B) reacting the polyurethane prepolymer with one or more isocyanatosilane (s) of the formula (I):

OCN-R-Si (R ¹ ) _m (-OR ² ) _3-m (I)

wherein m is 0, 1 or 2, each R ^{2 is} an alkyl group having 1 to 4 carbon atoms, each R ^{1 is} an alkyl group having 1 to 4 carbon atoms and R is a difunctional organic group.

The reaction of the polyurethane prepolymer with one or more isocyanatosilanes of the formula (I) according to (B) takes place in order to cap the hydroxyl groups of the prepolymer with the isocyanatosilane, or to introduce the silyl termination.

Another object of the present invention is a silylated polyurethane, which can be prepared by the above-described method according to the invention for preparing a silylated Polyurethane. The invention therefore also relates to a silylated polyurethane which is prepared by reacting at least one polyol compound A having a molecular weight of 4000 to 30 000 g / mol with a stoichiometric excess of at least one diisocyanate (relative to the polyol compound (s) A) and subsequent reaction of this first reaction product with a polyol mixture containing one or more polyol compound (s) B having a molecular weight of up to 2000 g / mol in an amount such that the sum of the polyol compounds A and B is in stoichiometric excess over the diisocyanate compound (s) or the diisocyanate (s) be used, whereby a polyurethane prepolymer is formed, which carries hydroxyl groups at the ends or is terminated by hydroxyl. In a subsequent reaction, this OH-group-bearing polyurethane prepolymer is reacted with one or more isocyanatosilanes of the formula (I) to cap the hydroxyl groups of the prepolymer with the isocyanatosilane, or to introduce the silyl termination, thereby forming a silylated polyurethane, the alkoxysilyl groups having reactive end groups.

Another object of the present invention is a moisture-curing adhesive, sealant or coating composition preparation and their use, which contains one or more silylated polyurethane (s) of the aforementioned type or prepared by the aforementioned method. In addition to the silylated polyurethane (s) of the present invention, this formulation may contain other ingredients, e.g. Plasticizers, fillers, catalysts and other auxiliaries and additives included.

The silylated polyurethanes produced by the process according to the invention are distinguished, in particular, by good extensibilities.

As polyol compounds or polyols, in principle, a plurality of at least two hydroxyl-carrying polymers may be used, for example polyesters, polyols, hydroxyl-containing polycaprolactones, hydroxyl-containing polybutadienes or polyisoprenes and their hydrogenation or hydroxyl-containing polyacrylates or polymethacrylates. It is also possible to use mixtures of different polyol compounds.

However, polyols are very particularly preferably polyoxyalkylenes, in particular polyethylene oxides and / or polypropylene oxides. Polyols containing polyethers as a polymer backbone have a flexible and elastic structure not only at the end groups but also in the polymer backbone. This can be used to produce compositions which have once again improved elastic properties. Polyethers are not only flexible in their backbone but also stable at the same time. For example, polyethers are not attacked or decomposed by water and bacteria, in contrast to, for example, polyesters.

Therefore, polyethylene oxides and / or polypropylene oxides are particularly preferably used.

The molecular weight M _{n of} the polymer backbone of the polyol compounds A is between 4000 and 30,000 g / mol (Dalton). According to a preferred embodiment of the invention, the molecular weight M _{n of} the polyol compound A is between 5000 and 25000 g / mol. Further particularly preferred molecular weight ranges are 8000 to 20,000 g / mol, very particularly preferred are 12,000 to 19,000 or 15,000 to 18,000 g / mol.

These molecular weights are particularly advantageous because compositions prepared using polyol compounds A having these molecular weights have viscosities that allow ready processability.

According to a preferred embodiment of the process according to the invention, a polyol compound A is used, in particular a polyoxyalkylene, in particular polyethylene oxide and / or polypropylene oxide.

Very particular preference is given to using polyoxyalkylenes, in particular polyethylene oxides or polypropylene oxides, which have a polydispersity PD of less than 2, preferably less than 1.5, in particular less than 1.3.

The molecular weight M _n is understood to mean the number average molecular weight of the polymer. This, as well as the weight-average molecular weight M _w , can be determined by gel permeation chromatography (GPC, also: SEC). This method is known to the person skilled in the art. The polydispersity is derived from the average molecular weights M _w and M _n . It is calculated as PD = M _w / M _n .

Particularly advantageous viscoelastic properties can be achieved if polyoxyalkylene polymers A which have a narrow molar mass distribution and thus low polydispersity are used as polymeric basic skeletons. These are for example by the way called double-metal cyanide catalysis (DMC catalysis) produced. These polyoxyalkylene polymers are generally distinguished by a particularly narrow molar mass distribution, by a high average molecular weight and by a very low number of double bonds at the ends of the polymer chains.

Such polyoxyalkylene polymers have a polydispersity PD (MJM _n ) of at most 1.7. Particularly preferred organic backbones are, for example, polyethers having a polydispersity of about 1:01 to about 1.3, more preferably about 1.05 to about 1.18, for example about 1.08 to about 1.1.1 or about 1.12 to about 1, 14. In a preferred embodiment of the invention, these polyethers have an average molecular weight (M _n ) of about 5,000 to about 30,000 g / mol, in particular about 6,000 to about 25,000 g / mol. Particularly preferred are polyethers having average molecular weights of about 10,000 to about 22,000 g / mol, in particular having average molecular weights of about 12,000 to about 18,000 or 15,000 to 18,000 g / mol.

The polyol compound B is also preferably a polyoxyalkylene. It has an average molecular weight (M _n ) of up to 2000 daltons or g / mol and may have a higher polydispersity than the polyol A. The number of double bonds at the ends of the polymer chains (terminal unsaturation) can be for the polyol B be greater than for the polyol compound A. Particularly preferred are average molecular weights (M _n ) of 500 to 1500 g / mol, in particular about 1000 g / mol.

Suitable diisocyanates for the preparation of the hydroxyl-terminated polyurethane prepolymer are, for example, ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,4-tetramethoxybutane diisocyanate, 1,6-hexamethylene diisocyanate (HDI), cyclobutane-1,3-diisocyanate, cyclohexane-1 , 3- and -1, 4-diisocyanate, bis (2-isocyanatoethyl) fumarate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatoethylcyclohexane (isophorone diisocyanate, IPDI), 2,4- and 2 , 6-Hexahydrotoluylendiisocyanat, hexahydro-1, 3- or -1, 4-phenylene diisocyanate, benzidine diisocyanate, naphthalene-1, 5-diisocyanate, 1, 6-diisocyanato-2,2,4-trimethylhexane, 1, 6-diisocyanato-2 , 4,4-trimethylhexane, xylylenediisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), 1, 3- and 1, 4-phenylenediisocyanate, 2,4- or 2,6-toluene diisocyanate (TDI), 2,4 ^' diphenylmethane diisocyanate, 2,2 - diisocyanate or ^{4,4-diphenylmethane} diisocyanate (MDI) and isomer mixtures thereof. Also suitable are partially or completely hydrogenated cycloalkyl of MDI, for example completely hydrogenated MDI (H12-MDI), alkyl-substituted diphenyl methane diisocyanates, for example mono-, di-, tri- or tetraalkyl as well as their partially or completely hydrogenated cycloalkyl, 4,4 ^{'-Diisocyanatophe} nylperfluoroethane, phthalic acid bis-isocyanatoethyl ester, 1-chloromethylphenyl-2,4- or -2,6- diisocyanate, 1-bromomethylphenyl-2,4-diisocyanate or 2,6, 3,3-bis-chloromethyl ether-4,4 ^'- diisocyanate, sulfur-containing diisocyanates such as by reaction of 2 mol of diisocyanate with 1 mol thiodiglycol or dihydroxydihexyl are available, the diisocyanates of Dimerfettsäuren, or mixtures of two or more of said diisocyanates, in question.

According to a preferred embodiment of the process according to the invention, the polyol mixture according to step (A) (ii) additionally contains at least one isocyanate-monofunctional compound. It is particularly preferred if this isocyanate-monofunctional compound is selected from monoalcohols, monomercaptans, monoamines or mixtures thereof. In this case, an amount of the polyol mixture is added so that the sum of the polyol compounds A and B and the monofunctional (isocyanate) compound (s) is used in a stoichiometric excess over the diisocanate compound (s). This means that the total number of hydroxyl groups of polyol compounds A and B and optionally monoalcohol and optionally SH or amine groups of monomercaptans or monoamines in stoichiometric excess over the isocyanate groups of the diisocyanate compound (s) is used, i. is higher than the number of isocyanate groups. It is preferred, however, if such a large excess is used that the sum of the polyol compounds A and B in a stoichiometric excess over the / the isocyanate compound (s) is used. In this case, the total number of hydroxyl groups of polyol compounds A and B is in the stoichiometric excess over the isocyanate groups of the diisocyanate compound (s), i. higher than the number of isocyanate groups. Particularly preferred is the use of a polyol mixture consisting of one or more polyol compound (s) B and at least one isocyanate monofunctional compound, for example. A polyol mixture consisting of a polyol compound B and a monofunctional to isocyanates compound.

Thus, the functionality of the resulting silylated polyurethanes can be controlled so that, for example, a preferred degree of silylation or degree of silyl termination can be adjusted from 1.5 to less than 2.0, in particular from 1.6 to 1.8. This has the advantage that the resulting silylated polyurethanes again increased extensibility and good elasticity with low modulus of elasticity (E-50, E-100), in particular less than 0.5 N / mm ² , more preferably less than 0.4 N / mm ² .

According to the invention are suitable as (against isocyanates) monofunctional compounds such compounds, the isocyanate-reactive groups having a functionality of 1 have. In principle, all monofunctional alcohols, amines or mercaptans are suitable for this purpose, these are in particular monofunctional alcohols (monoalcohols) having up to 36 carbon atoms, monofunctional primary and / or secondary amines (monoamines) having up to 36 carbon atoms or monofunctional mercaptans (monomercan) with up to 36 carbon atoms. However, it is also possible to use mixtures of polyalcohols, polyamines and / or polymercaptans as monofunctional compounds, as long as their average functionality is significantly less than 2.

Particular preference is given, for example, to monoalcohols such as benzyl alcohol, methanol, ethanol, the isomers of propanol, butanol and hexanol, monoethers of ethylene glycol and / or diethylene glycol, and the primary alcohols having 8 to 18 carbon atoms obtainable by reduction of fatty acids, such as octanol, decanol , Dodecanol, tetradecanol, hexadecanol and octadecanol, especially in the form of technical mixtures thereof. Monoalcohols having 4 to 18 carbon atoms are preferred, since the lower alcohols are difficult to prepare anhydrous.

Also usable are monoalkylpolyether alcohols of different molecular weight, with a number average molecular weight between 1000 and 2000 g / mol being preferred. A preferred representative is z. B. monobutyl propylene glycol.

It is also possible to use saturated fatty alcohols having up to 26 carbon atoms, preferably those containing up to 22 carbon atoms, which are synthesized industrially by reduction (hydrogenation) of fatty acid methyl esters. Examples include: caproic alcohol, caprylic alcohol, pelargonyl alcohol, capric alcohol, lauric alcohol, myristic alcohol, cetyl alcohol, stearyl alcohol, gadoleyl alcohol and behenyl alcohol or the guerbet alcohols 2-hexyldecanol, 2-octyldodecanol, 2-decyltetradecanol, 2-dodecylhexadecanol, 2-tetradecyl-octadecanol, 2 Hexadecyleicosanol, guerbet alcohol from erucyl alcohol, behenyl alcohol and octenols.

Optionally, mixtures resulting from the guerbetization of the technical fatty alcohols, together with the other aforementioned alcohols, may be used.

In the preparation of the silylated polyurethanes according to the invention or in the process according to the invention, the polyol compound A is first reacted in a first step with a stoichiometric excess of a diisocyanate compound or of a diisocyanate. In the subsequent step, this reaction mixture, the polyol compound B and optionally the monofunctional compound (in the presence of isocyanates) in such a stoichiometric excess that a hydroxyl-terminated polyurethane prepolymer is formed. The proportion of the polyol compound (s) B used is preferably 25 to 150 mol% of the polyol compound A. That is, the polyol compound (s) B preferably accounts for 20 to 60 mol% based on the total content of the polyol compounds A and B, and accordingly Proportion of the polyol compound (s) A is 40 to 80 mol%. The proportion of monofunctional compound (s) (to isocyanates) is preferably from 0 to 40 mole percent, based on the polyol mixture containing polyol compound (s) B and at least one (to isocyanates) monofunctional compound; Particularly preferred is a proportion of monofunctional compound (s) of 15 to 30 mole percent. The proportion of monofunctional (compared to isocyanates) compound is vorzusgsweise up to 40 mol%, in particular 10 to 40 mol.%., Preferably 15 to 30 mol.%, Most preferably 10 to 20 mol% of the mixture of polyol compounds or polyols A and B and the (compared to isocyanates) monofunctional compound or based on the total content of the polyol compounds A and B and the monofunctional (isocyanate) compound. In a subsequent reaction, the hydroxyl-terminated polyurethane prepolymer is reacted with one or more isocyanatosilanes of the formula (I) in such a way that the hydroxyl groups are completely capped by the isocyanatosilane.

The stoichiometric excess of the sum of polyol compounds A and B and optionally monofunctional compound with respect to the diisocyanate compound or mixture of diisocyanates used is 1, 1 to 2.0, preferably between 1, 2 and 1, 5. This ensures that the step A reaction product forms a hydroxyl-terminated polyurethane prepolymer.

For the subsequent reaction of the hydroxyl-terminated polyurethane prepolymer with one or more isocyanatosilanes or isocyanato-functional alkoxysilanes of the formula (I), the following isocyanatosilanes are suitable:

Methyldimethoxysilylmethylisocyanat, Ethyldimethoxysilylmethylisocyanat, Methyldiethoxysilylmethylisocyanat, Ethyldiethoxysilylmethylisocyanat, metal thyldimethoxysilylethylisocyanat, Ethyldimethoxysilylethylisocyanat, Methyldiethoxy- silylethylisocyanat, Ethyldiethoxysilylethylisocyanat, Methyldimethoxysilylpropylisocyanat, Ethyldimethoxysilylpropylisocyanat, Methyldiethoxysilylpropylisocyanat, Ethyldiethoxysilylpropylisocyanat, Methyldimethoxysilylbutylisocyanat, Ethyldimethoxysilyl- butyl isocyanate, Methyldiethoxysilylbutylisocyanat, Diethylethoxysilylbutylisocyanat, Ethyldiethoxysilylbutylisocyanat, Methyldimethoxysilylpentylisocyanat, Ethyldi- methoxysilylpentylisocyanat, pentyl isocyanate Methyldiethoxysilylpentylisocyanat, Ethyldiethoxysilyl-, Methyldimethoxysilylhexylisocyanat, Ethyldimethoxysilylhexylisocyanat, Methyldiethoxysilylhexylisocyanat, Ethyldiethoxysilylhexylisocyanat, trimethoxysilyl methylisocyanate, Triethoxysilylmethylisocyanat, Trimethoxysilylethylisocyanat, triethoxy silylethylisocyanat, trimethoxysilylpropylisocyanate, triethoxysilylpropylisocyanate, Trimethoxysilylbutylisocyanat, Triethoxysilylbutylisocyanat, Trimethoxysilylpentylisocyanat, Triethoxysilylpentyl isocyanate, trimethoxysilylhexyl isocyanate, triethoxysilylhexyl isocyanate.

R is preferably a divalent aliphatic hydrocarbon group and may be saturated or unsaturated, and preferably has a main chain of 1 to 6 carbon atoms, preferably methylene, ethylene or propylene. Particularly preferred are 2 to 6 carbon atoms. With particular preference R is furthermore a difunctional straight-chain or branched alkyl radical having 1 to 6, in particular 2 to 6, carbon atoms.

In another preferred embodiment, R is -CH ₂ -. Such compounds have a high reactivity of the silyl groups, which contributes to shortening the setting and curing times.

In another preferred embodiment, R is - (CH ₂ ) 3-. If a propylene group is chosen for R, then these compounds have a particularly high flexibility. This property is attributed to the longer linking carbon chain, since methylene groups are generally flexible and mobile.

Preferably, m is zero or one, ie the isocyanato-functional alkoxysilane or isocyanatosilane carries a trialkoxy or dialkoxy group. In general, polymers which contain di- or trialkoxysilyl groups have highly reactive attachment sites which enable rapid curing, high degrees of crosslinking and thus good final strengths. Another advantage of such polymers containing alkoxy groups is the fact that when cured under the influence of moisture alcohols are formed, which are harmless in the released amounts and evaporate. Therefore, such compositions are particularly suitable for the home improvement sector. The particular advantage of using dialkoxysilyl groups is that the corresponding compositions after curing are more elastic, softer and more flexible than systems containing trialkoxysilyl groups. They are therefore especially for an application suitable as sealants. In addition, they cease even less alcohol when curing and are therefore of particular interest when the amount of alcohol released is to be reduced.

With trialkoxysilyl groups, on the other hand, a higher degree of crosslinking can be achieved, which is particularly advantageous if a harder, stronger mass is desired after curing. In addition, trialkoxysilyl groups are more reactive, ie they crosslink faster and thus reduce the required amount of catalyst; and they have advantages in the "cold flow" - the dimensional stability of a corresponding adhesive under the influence of force and possibly temperature action - on.

As alkoxy groups, in particular methoxy, ethoxy, propyloxy and butoxy groups are selected.

In particular, an embodiment is preferred in which R ¹ and R ^{2 are} a methyl group. Depending on the nature of the alkyl radicals on the oxygen atom, compounds having alkoxysilyl groups have different reactivities in chemical reactions. Within the alkoxy groups, the methoxy group shows the greatest reactivity. It is thus possible to resort to silyl groups of this type if particularly rapid curing is desired. Higher aliphatic radicals such as ethoxy bring about a lower reactivity of the terminal alkoxysilyl group compared to methoxy groups and can advantageously be used for the development of graduated crosslinking rates. In addition to methoxy and ethoxy groups, it is of course also possible to use larger radicals than hydrolyzable groups, which naturally have a lower reactivity. This is of particular interest when a delayed curing is desired, for example, in adhesives, which should allow even after the application still a shift of the bonded surfaces against each other to find the final position.

Particular preference is given to methyldimethoxysilylmethyl isocyanate, methyldiethoxysilylmethyl isocyanate, methyldimethoxysilylpropyl isocyanate and ethyldimethoxysilylpropyl isocyanate or their trialkoxy analogues, in particular trimethoxysilylpropyl isocyanate or 3-isocyanatopropyltrimethoxysilane or triethoxysilylpropyl isocyanate or 3-isocyanatopropyltriethoxysilane.

The isocyanatosilane (s) are used in at least a stoichiometric amount to the hydroxyl groups of the polyurethane prepolymer, but is preferably a lower stoichiometric excess of the isocyanatosilanes over the hydroxyl groups. This stoichiometric excess of the isocyanatosilanes over the hydroxyl-containing prepolymers is between 4 and 15 equivalent percentages, preferably between 5 and 10 equivalent percentages based on the isocyanate grouping.

Another object of the present invention is a silylated polyurethane, which can be prepared by the above-described process according to the invention for preparing a silylated polyurethane. Such a silylated polyurethane is accordingly preparable by a process comprising:

(A) React

(i) at least one polyol compound A having a molecular weight of 4,000-30,000 g / mol with at least one diisocyanate at a stoichiometric excess of the diisocyanate compound (s) over the polyol compound (s) A, followed by the addition

(ii) a polyol mixture containing one or more polyol compound (s) B having a molecular weight of up to 2000 g / mol in an amount such that the sum of the polyol compounds A and B are used in stoichiometric excess over the diisocyanate compound (s), thereby forming a polyurethane prepolymer which is hydroxyl terminated; and

OCN-R-Si (R ¹ ) _m (-OR ² ) _3-m (I)

The embodiments described for the method according to the invention therefore also apply to the silylated polyurethane according to the invention.

In particular, according to a particularly preferred embodiment, the polyol mixture according to step (A) (ii) additionally comprises at least one isocyanate-monofunctional compound. It is particularly preferred if these are isocyanates monofunctional compound is selected from monoalcohols, monomercaptans, monoamines or mixtures thereof.

Another object of the present invention is a silane-crosslinking, curable composition comprising at least one silylated polyurethane obtainable by the process according to the invention or at least one silylated polyurethane according to the invention.

Another object of the present invention is the use of a preparation comprising one or more silylated (s) polyurethane (s) preparable by the process according to the invention or one or more inventive silylated (s) polyurethane (s) or a composition according to the invention as an adhesive, or Sealant or as a coating agent.

The adhesive and sealant compositions and preparations according to the invention may contain, in addition to the abovementioned silylated polyurethane compounds, other auxiliaries and additives which impart improved elastic properties, improved resilience, sufficiently long processing time, fast curing rate and low residual tackiness to these formulations. These auxiliaries and additives include, for example, plasticizers, stabilizers, antioxidants, fillers, thinners or reactive diluents, drying agents, adhesion promoters and UV stabilizers, fungicides, flame retardants, pigments, rheological aids, color pigments or color pastes and / or, if appropriate, also small amounts of solvent ,

Suitable plasticizers are, for example, adipic acid esters, azelaic acid esters, benzoic acid esters, butyric acid esters, acetic acid esters, esters of higher fatty acids containing from about 8 to about 44 carbon atoms, esters containing OH groups or epoxidized fatty acids, fatty acid esters and fats, glycolic esters, phosphoric esters, phthalic acid esters, from 1 to 12 C-atoms containing linear or branched alcohols, propionic acid esters, sebacic acid esters, sulfonic acid esters, thiobutyric acid esters, trimellitic acid esters, citric acid esters and esters based on nitrocellulose and polyvinyl acetate, and mixtures of two or more thereof. Particularly suitable are the asymmetric esters of adipic acid monooctyl ester with 2-ethylhexanol (Edenol DOA, Fa. Cognis Germany GmbH, Dusseldorf) or esters of abietic acid.

For example, of the phthalic acid esters dioctyl phthalate (DOP), dibutyl phthalate, diisoundecyl phthalate (DIUP) or butyl benzyl phthalate (BBP), of the adipates dioctyl adipate (DOA), diisodecyl adipate, diisodecyl succinate, dibutyl sebacate or butyl oleate. The pure or mixed ethers are also suitable as plasticizers monofunctional, linear or branched C ₄ i ₆ alcohols or mixtures of two or more different ethers of such alcohols, for example dioctyl (available as Cetiol OE. Cognis Germany GmbH, Dusseldorf).

Further suitable plasticizers are end-capped polyethylene glycols. For example, polyethylene or polypropylene glycol di-C- _M- alkyl ethers, in particular the dimethyl or diethyl ethers of diethylene glycol or dipropylene glycol, and mixtures of two or more thereof.

However, particularly preferred are end-capped polyethylene glycols, such as polyethylene or polypropylene glycol dialkyl ethers, where the alkyl radical is one to four C atoms, and in particular the dimethyl and diethyl ethers of diethylene glycol and dipropylene glycol. Especially with dimethyldiethylene glycol, an acceptable cure is achieved even under less favorable application conditions (low humidity, low temperature). For more details on plasticizers reference is made to the relevant literature of technical chemistry.

Plasticizers may be used in the formulations between 0 and 40, preferably between 0 and 20% by weight (based on the total composition) in the preparation.

"Stabilizers" in the context of this invention are to be understood as meaning antioxidants, UV stabilizers or hydrolysis stabilizers. Examples of these are the commercially available sterically hindered phenols and / or thioethers and / or substituted benzotriazoles and / or amines of the "HALS" type (Hindered Amine Light Stabilizer). It is preferred in the context of the present invention, when a UV stabilizer is used, which carries a silyl group and is incorporated in the final product during curing or curing. Particularly suitable for this purpose are the products Lowilite 75, Lowilite 77 (Great Lakes, USA). It is also possible to add benzotriazoles, benzophenones, benzoates, cyanoacrylates, acrylates, sterically hindered phenols, phosphorus and / or sulfur. The preparation according to the invention may contain up to about 2% by weight, preferably about 1% by weight, of stabilizers. Furthermore, the preparation according to the invention may further contain up to about 7% by weight, in particular up to about 5% by weight, of antioxidants. Catalysts which can be used are all known compounds which can catalyze the hydrolytic cleavage of the hydrolyzable groups of the silane groups and the subsequent condensation of the Si-OH group to form siloxane groups (crosslinking reaction or adhesion-promoting function). Examples include titanates such as tetrabutyl titanate and tetrapropyl titanate; Bismuth compounds such as bismuth tris 2-ethylhexanoate, tin carboxylates such as dibutyltin dilaurate (DBTL), dibutyltin maleate, Dibutylzinndiethylhexanoat, dibutyltin dioctoate, Dibutylzinndimethylmaleat, Dibutylzinndiethylmaleat, Dibutylzinndibutyl-, Dibutylzinndiiosooctylmaleat, Dibutylzinnditridecylmaleat, Dibutylzinndibenzylmaleat, dibutyltin maleate, dibutyltin diacetate, Zinnoctaoat, Dioctylzinndistealeat, Dioctylzinndilaulat, Dioctylzinndiethylmaleat, Dioctyltin diisooctylmaleate, dioctyltin diacetate, and tin naphthenoate; Tin alkoxides such as dibutyltin dimethoxide, dibutyltin diphenoxide, and dibutyltin diisoproxide; Tin oxides such as dibutyltin oxide, and dioctyltin oxide; Reaction products between dibutyltin oxides and phthalic acid esters, dibutyltin bisacetylacetonate; Organoaluminum compounds such as aluminum trisacetylacetonate, aluminum trisethylacetoacetate, and diisopropoxyaluminum ethylacetoacetate; Chelate compounds such as zirconium tetraacetylacetonate, and titanium tetraacetylacetonate; lead octanoate; Amine compounds or their salts with carboxylic acids, such as butylamine, octylamine, laurylamine, dibutylamine, monoethanolamine, diethanolamine, triethanolamine, diethylenetriamine, triethylenetetramine, oleylamines, cyclohexylamine, benzylamine, diethylaminopropylamine, xylylenediamine, triethylenediamine, guanidine, diphenylguanidine, 2,4,6-tris ( dimethylaminomethyl) phenol, morpholine, N-methylmorpholine and 1,8-diazabicyclo- (5,4,0) -undecene-7 (DBU), a low molecular weight polyamide resin obtained from an excess of a polyamine and a polybasic acid adducts of a polyamine in excess with an epoxide, silane coupling agent with amino groups, such as 3-aminopropyltrimethoxysilane, and N- (β-aminoethyl) -aminopropylmethyl-dimethoxysilane. The catalyst, preferably mixtures of several catalysts, are used in an amount of from 0.001 to about 5% by weight, based on the total weight of the preparation. Preferred are wt .-% of 0.01 to 1, in particular 0.03 to 0.5, particularly preferably less than 0.1, wt .-% catalyst, based on the total weight of the preparation.

The composition or preparation according to the invention may additionally contain fillers. For example, chalk, limestone, precipitated and / or fumed silica, zeolites, bentonites, magnesium carbonate, kieselguhr, clay, clay, talc, titanium oxide, iron oxide, zinc oxide, sand, quartz, flint, mica, glass powder and other ground minerals are suitable here. Furthermore, organic fillers can also be used, in particular carbon black, graphite, wood fibers, wood flour, sawdust, cellulose, cotton, pulp, cotton, Wood chips, chaff, chaff, ground walnut shells and other fiber cuts. Furthermore, short fibers such as glass fiber, glass filament, polyacrylonitrile, carbon fiber, Kevlar fiber or even polyethylene fibers can be added. Aluminum powder is also suitable as a filler.

The pyrogenic and / or precipitated silicas advantageously have a BET surface area of from 10 to 90 m ² / g, in particular from 35 to 65 m ² / g. When used, they do not cause any additional increase in the viscosity of the preparation according to the invention, but contribute to an enhancement of the cured preparation.

Particular preference is given to using a highly disperse silica having a BET surface area of 45 to 55 m ² / g, in particular having a BET surface area of about 50 m ² / g. Such silicas have the additional advantage of a 30 to 50% shortened incorporation time compared to silicic acids with a higher BET surface area. Another advantage is that the above-mentioned highly dispersed silicic acid can be incorporated into silane-terminated adhesives, sealants or coating materials in a considerably higher concentration without impairing the flow properties of the adhesives, sealants or coating materials.

It is also conceivable to use pyrogenic and / or precipitated silicas having a higher BET surface area, advantageously 100-250 m ² / g, in particular 110-170 m ² / g, as filler. Due to the higher BET surface area, one can achieve the same effect, eg reinforcement of the cured preparation, at a lower weight proportion of silica. Thus, one can use other substances to improve the preparation according to the invention in terms of other requirements.

Also suitable as fillers are hollow spheres with a mineral shell or a plastic shell. These may be, for example, glass bubbles, which are commercially available under the trade names Glass Bubbles®. Plastic-based hollow spheres are e.g. available under the trade names Expancel® or Dualite®. These are composed of inorganic or organic substances, each having a diameter of 1 mm or less, preferably 500 μm or less.

For some applications, fillers are preferred which impart thixotropy to the formulations. Such fillers are also described as rheological additives or auxiliaries, for. As silica gels, aerosils, coal, carbon black or swellable plastics such as PVC. Furthermore, the following organic additives can be used as rheological modifiers: hydrogenated Castor oil, fatty acid amides, urea derivatives and polyurea derivatives. In order to be easily pressed out of a suitable metering device (eg tube), such preparations have a viscosity of 30,000 to 150,000, preferably 40,000 to 80,000 mPas, in particular 50,000 to 60,000 mPas or even 3,000 to 15,000 mPas.

The fillers are preferably used in an amount of from 1 to 80% by weight, preferably from 5 to 60% by weight, based on the total weight of the preparation.

Examples of suitable pigments are titanium dioxide, iron oxides or carbon black.

It often makes sense to further stabilize the preparations according to the invention by drying agents against penetrating moisture, in order to further increase the shelf life. Occasionally there is also a need to lower the viscosity of the adhesive or sealant according to the invention for certain applications by using a reactive diluent. As reactive diluents, it is possible to use all compounds which are miscible with the adhesive or sealant with reduction of the viscosity and have at least one moisture-crosslinking or binder-reactive group.

As a reactive diluent, e.g. use the following substances: polyalkylene glycols reacted with isocyanatosilanes (eg Synalox 100-50B, DOW), carbamatopropyltrimethoxysilane, alkyltrimethoxysilane, alkyltriethoxysilane, such as methyltrimethoxysilane, methyltriethoxysilane and vinyltrimethoxysilane (VTMO, Geniosil XL 10, Wacker), vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, octyltrimethoxysilane, Tetraethoxysilane, vinyldimethoxymethylsilane (XL12, Wacker), vinyltriethoxysilane (GF56, Wacker), vinyltriacetoxysilane (GF62, Wacker), isooctyltrimethoxysilane (IOtrimethoxy), isooctyltriethoxysilane (IOtriethoxy, Wacker), N-trimethoxysilylmethyl-O-methylcarbamate (XL63, Wacker), N-dimethoxy (methyl) silylmethyl-O-methyl-carbamate (XL65, Wacker),

Hexadecyltrimethoxysilane, 3-octanoylthio-1-propyltriethoxysilane and partial hydrolysates of these compounds.

Further, the following polymers are also available from Kaneka Corp. can be used as reactive diluent: MS S203H, MS S303H, MS SAT 010, and MS SAX 350.

It is likewise possible to use silane-modified polyethers which are derived, for example, from the reaction of isocyanatosilane with Synalox types. A large number of the abovementioned silane-functional reactive diluents simultaneously have a drying and / or adhesion-promoting action in the preparation. These reactive diluents are used in amounts of between 0.1 and 15% by weight, preferably between 1 and 5% by weight, based on the total composition of the preparation.

An adhesion promoter is understood as meaning a substance which improves the adhesive properties of adhesive layers on surfaces. One or more adhesion promoters may be included. Also suitable as adhesion promoters are so-called tackifiers such as hydrocarbon resins, phenolic resins, terpene-phenolic resins, resorcinol resins or their derivatives, modified or unmodified resin acids or esters (abietic acid derivatives), polyamines, polyaminoamides, anhydrides and anhydride-containing copolymers. Even the addition of polyepoxide resins in small amounts may improve the adhesion of some substrates. For this purpose, preferably the solid epoxy resins having a molecular weight of more than 700 in finely ground form are used. If tackifiers are used as adhesion promoters, their type and amount depends on the adhesive / sealant composition and on the substrate to which it is applied. Typical tackifying resins (tackifiers) such as e.g. Terpene-phenolic resins or resin acid derivatives are used in concentrations of between 5 and 20% by weight, typical adhesion promoters such as polyamines, polyaminoamides or phenolic resins or resorcinol derivatives are in the range between 0.1 and 20% by weight, in particular 0.5 to 10, particularly preferably 1 to 5 Wt .-%, based on the total composition of the preparation used. Particularly suitable silane coupling agents, in particular alkoxysilanes, with a (further) functional group such. an amino group, a mercapto group, an epoxy group, a carboxyl group, a vinyl group, an isocyanate group, an isocyanurate group or a halogen. Examples are γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, β-carboxyethyltriethoxysilane, β-carboxyethylphenylbis (2-methoxyethoxy) silane, N-β- (carboxymethyl) aminoethyl -γ-aminopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-acroyloxypropylmethyltriethoxysilane, Y-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropylmethyldimethoxysilane, tris (trimethoxysilyl) isocyanurate and γ-chloropropyltrimethoxysilane.

Particularly preferred coupling agents are, in particular, aminosilanes (amino-functional alkoxysilanes or aminoalkylalkoxysilanes), such as, for example, γ-aminopropyltrimethoxysilane, Aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, y-

Aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ- (2-aminoethyl) -3-aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropyltriethoxysilane, γ- (2-aminoethyl) aminopropylmethyldiethoxysilane, γ- (2- Aminoethyl) aminopropyltriisopropoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-benzyl-γ-aminopropyltrimethoxysilane, and N-vinylbenzyl-γ-aminopropyltriethoxysilane, or oligomeric aminosilanes, such as aminoalkyl group-modified alkylpolysiloxane (Dynasylan 1146).

The preparation of the preparation according to the invention is carried out by known methods by intimately mixing the ingredients in suitable dispersing, z. As fast mixer, kneader, planetary mixer, planetary dissolver, internal mixer, so-called "Banbury mixer", twin-screw extruder and similar mixing units known in the art.

A preferred embodiment of the preparation according to the invention may contain:

From 5 to 50% by weight, preferably from 10 to 40% by weight, of one or more compounds of the silylated polyurethanes according to the invention,

0 to 30% by weight, in particular less than 20% by weight, more preferably less than 10% by weight of plasticizer, e.g. 0.5-30, in particular 1-25 wt.% Plasticizer,

- 0 to 80 wt .-%, preferably 20 to 60 wt .-%, particularly preferably 30 to 55 wt .-% fillers.

Furthermore, the embodiment may contain other adjuvants, e.g. 0 - 10 wt .-%, in particular 0.5 - 5 wt .-%.

The total of all components adds up to 100 wt .-%, wherein the sum of the main components listed above does not have to add up to 100 wt .-%.

The silylated polyurethane prepolymers according to the invention cure with the ambient air humidity to low-modulus polymers, so that low modulus, moisture-curing adhesive and sealant preparations and coatings and pressure-sensitive adhesives can be produced from these prepolymers with the aforementioned auxiliaries and additives.

In the following embodiments, the invention will be explained in more detail, the selection of examples is not intended to represent a limitation of the scope of the subject invention. Examples

Preparation of the silane-terminated polyurethane prepolymers:

The polyols and monoalcohols used were dried before the reaction in a 2000 ml three-necked flask at 80 ⁰ C in a vacuum.

The following polyols and isocyanate compounds were used:

Polyol A: polyoxypropylene glycol, MW 8000 functionality 2, OH number 13.6, Acclaim 8000, Fa.

Bavarian

Diisocyanate: TMXDI (m-tetramethylxylene diisocyanate)

Polyol B: Polyoxypropylene glycol, MW 2000, functionality 2, OH number 56, Lupranol 1000, Fa.

BASF

Monoalcohol: ethylhexanol

3-isocyanatopropyltrimethoxysilane, Geniosil GF 40, from Wacker

Polyol A is charged with the diisocyanate and reacted at 80 ° C with catalysis with DBTL to form an NCO-terminated prepolymer. As soon as the theoretically calculated NCO value is reached, successive first monoalcohol and then the polyol B are added with vigorous stirring. It is stirred for half an hour at 80 ⁰ C, added isocyanatosilane and stirred for a further half an hour. Subsequently, the addition of 1, 5% UV stabilizer and 2% VTMO added.

In accordance with the above general preparation instructions, the silane-terminated polyurethanes listed in Table 1 below were prepared, the quantities given are grams or millimoles:

Table 1

Test conditions for the cured polymer films

Of the mixtures according to Table 1 skin-over-time (SOT) and the

Time to form a tack-free layer (tack free time / TFT) determined.

Furthermore, the abovementioned mixtures were formulated (100 parts of polymer + 1 part of aminosilane (Geniosil GF 91) + 0.2 parts of DBTL) and applied in a layer thickness of 2 mm to glass plates covered with polyether film. After 7 days of storage (23 ° C., 50% relative humidity), samples were punched out of these films (S2 specimens) and the mechanical data (modules at 50%, 100% and 200% elongation and elongation at break, based on DIN EN 27389 and DIN EN 28339. The viscosity (Brookfield RVT viscometer) of the uncured polymer mixtures is also listed

Table 2 summarizes the measurement results.

Table 2

As can be seen from Table 2, the cured films of the compositions of the invention give low modulus, soft elastic polymer films.

Claims

claims

A process for producing a silylated polyurethane, comprising:

(A) React

(ii) a polyol mixture containing one or more polyol compound (s) B having a molecular weight of up to 2000 g / mol in an amount such that the sum of the polyol compounds A and B are used in a stoichiometric excess over the diisocyanate compound (s) Polyurethane prepolymer is formed, which is hydroxyl-terminated; and

OCN-R-Si (R ¹ ) _m (-OR ² ) _3-m (I)

2. The method according to claim 1, characterized in that the polyol mixture additionally contains at least one isocyanate monofunctional compound selected from monoalcohols, monomercaptans, monoamines or mixtures thereof.

3. The method according to claim 1 or 2, characterized in that R is a difunctional straight or branched alkyl radical having 1 to 6, in particular 2 to 6, carbon atoms.

4. The method according to at least one of claims 1 to 3, characterized in that m is zero or one.

5. The method according to at least one of claims 1 to 4, characterized in that the proportion of the polyol compound B is 25 to 150 mol% of the polyol compound A.

6. The method according to at least one of claims 2 to 5, characterized in that the proportion of isocyanate monofunctional compound 10 to 40 mol%, preferably 15 to 30 mol%, based on the total content of the polyol compounds A and B and the isocyanate monofunctional compound is.

7. The method according to at least one of claims 1 to 6, characterized in that the isocyanatosilane of the formula (I) is 3-isocyanatopropyltrimethoxysilane or 3-isocyanatopropyltriethoxysilane.

8. Silylated polyurethane producible by a process comprising:

(A) React

OCN-R-Si (R ¹ ) _m (-OR ² ) _3-m (I)

9. silylated polyurethane according to claim 8, characterized in that the

Polyol mixture additionally contains at least one isocyanate monofunctional compound selected from monoalcohols, monomercaptans, monoamines or mixtures thereof.

10. silylated polyurethane according to claim 8 or 9, characterized in that the proportion of the polyol compound B is 25 to 150 mol% of the polyol A is.

1 1. Silylated polyurethane according to claim 9 or 10, characterized in that the proportion of the monofunctional compound is 10 to 40 mol%, preferably 15 to 30 mol%, based on the total content of the polyol compounds A and B and the isocyanate monofunctional compound.

12. Silylated polyurethane according to at least one of claims 8 to 11, characterized in that R is a difunctional straight or branched alkyl radical having 1 to 6, in particular 2 to 6, carbon atoms and / or m is zero or one.

13. Silylated polyurethane according to at least one of claims 8 to 12, characterized in that the isocyanatosilane of the formula (I) is 3-isocyanatopropyltrimethoxysilane or 3-isocyanatopropyltriethoxysilane and / or the diisocyanate compound is selected from the group consisting of 2, 4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 4,4'-dicyclohexylmethane diisocyanate isomers, tetramethylxylylene diisocyanate (TMXDI), and mixtures thereof.

14. A silane-crosslinking, curable composition comprising at least one silylated polyurethane obtainable by a process according to any one of claims 1 to 7 or at least one silylated polyurethane according to any one of claims 8 to 13.

15. Use of a preparation comprising one or more silylated polyurethane (s) preparable by a process according to any one of claims 1 to 7 or one or more silylated polyurethane (s) according to at least one of claims 8 to 13 or a A composition according to claim 14 as an adhesive or sealant or as a coating agent.